A new, lightweight, carbon composite crane mast and telescopic boom is being developed by a collaborative research and development (R&D) project team in the Czech Republic. The project is based upon the use of an advanced automated composite process which uses robot assisted filament placement to manufacture stiff, high strength continuous fibre structures and integrated composite connections.
The new concept composite crane design is looking to offer a much lighter and cost effective alternative to existing mobile hydraulic telescopic cranes and marine davits currently manufactured from steel. The project is part of the government funded TRIO Program initiative, financed through the Czech Republic Ministry of Industry and Trade. The TRIO Program aims to drive greater innovation nationally in key enabling technologies such as photonics, micro/nano electronics nanotechnology, biotechnology, advanced materials and advanced manufacturing.
The innovation project is an academic and commercial partnership between Compo Tech PLUS, spol. s r.o and the Regional Institute of Technology (RTI), which is the Faculty of Mechanical Engineering research centre at the University of West Bohemia in Pilsen. Dr. Ondřej Uher, R&D Director for CompoTech explains how the project work is divided between the two teams: “The CompoTech engineering team is responsible for project management, the design concept development and finalization, along with the production of all functional test samples and the epoxy carbon composite mast and telescopic boom crane components. The RTI team is focused on creating the CAD models and kinematic analyses, setting the properties and performance in use specifications against crane standards, and is carrying out the testing program of all the key design parameters and components, including dynamic fatigue testing of the final assembled proof of concept composite telescopic crane”.
The carbon composite compact crane design is based on the dimensions and performance parameters of an existing mobile hydraulic steel telescopic crane. However, the component design and production method for manufacturing all the carbon epoxy components for the mast and boom is very different. The composite mast has two interconnected components, a lower square base section and a tapered upper mast section. The telescopic boom is made up of three interconnected octagonal profile sections which fit into each other. [See schematic CAD drawing: CompoTech/RTI TRIO program carbon composite telescopic crane diagram.]
The innovative composite design uses CompTech’s proprietary automated axial carbon fibre placement technology to manufacture the hollow, epoxy carbon mast and octagonal telescopic boom sections of the crane. The high strength joints and fixture points on the mast and outermost boom section are manufactured using CompoTech’s continuous fibre integrated loop technology (ILT); other projects have successfully used ILT to overcome joint design issues between sub-assembly components, enabling the production of much higher strength, fully integrated, joint holes for bolts which do not require drilling or overlaminating. The combination of these technologies produces carbon fibre reinforced epoxy components with an E Modulus of 327 GPa, which is 69% stiffer than stainless steel (193 GPa) and 56% stiffer than tool steel (210 GPa), which are also a quarter of the mass.
The carbon composite crane is expected be cost competitive as it can be produced using an automated process and eliminates the need for welding or heat treatment. Depending on the application, a composite coating system can be used instead of a multilayer paint system which often needs reapplication over time. In addition to offering a major weight saving over steel, the composite system will require less maintenance over its lifetime, not being susceptible to corrosion from the elements, especially salt water. The carbon composite crane is expected to be particularly beneficial for mobile, telescopic cranes fitted on commercial and military vehicles, and for davits on smaller workboats and offshore platforms.
The project has reached a key ‘proof of concept’ milestone, having completed both static and dynamic testing of the fully assembled crane. The performance results obtained indicate that it should be possible to manufacture a compact composite telescopic crane using CompoTech’s carbon fibre placement and ILT technologies that will be able to provide similar lifting capabilities to an equivalent sized steel crane, with around 50% less weight.
Dr. Humphrey Carter, CompoTech’s Head of Business Development commented: “The project has reached an important proof of concept stage. The results from the tests carried out by RTI are very encouraging, so much so that we believe that we have a design that could progress to commercialisation. At this stage, we are very interested to speak with potential crane manufacturers who would like to become a collaborative partner for the next development stages of the project to work with us to fully develop and field test the final product design and to evaluate the commercial opportunity and viability of manufacturing and supplying a lightweight carbon composite crane to key target markets and applications.”